We are seeing a lot of examples of Renotherm and Icynene roof insulation at the moment - and have bitter experience of many past cases.

Spray foam roof insulation is death to your roof.  It is also toxic.  It is a fire hazard.  It destroys your roof.  It massively devalues your home.  

OK - did you get all of that?

Spray foam insulation - Renotherm and Icynene are two common trade names, is PIR foam sprayed onto the underside of the roof.  It is non-breathable and toxic as hell when it burns - releasing cyanide gas. It is the same chemical as the foams that burned in the Grenfell Tower disaster. What killed people in Grenfell was not so much fire, but smoke - toxic, cyanide laden smoke.  

In the past few months we've seen and documented a number of cases of very wet roof timbers, with degradation of the roof as a result of sprayed foam insulation.  These were both open and closed cell foam - and all had effectively destroyed the roof they were sprayed in.  The manufacturers of this stuff are toxic chemical companies, who fight each other to sell the benefits of 'open cell, versus closed cell' or water sprayed, or whatever - but the bottom line is that these are NOT breathable as claimed. We have documented proof that they cause major problems with roofing.  We have seen numerous purchasers walk away from deals after finding this stuff sprayed in the roof.  One supplier made the news recently and was prosecuted by Trading Standards for their heroic efforts to insulate vulnerable old peoples homes with toxic rubbish: Cold Hearted Crooks

In the USA they have woken up to this: It can make your home unliveable

They also appeared on a recent TV program on the fraud of sprayed foam roof insulation - 

Note that they will often try to claim they have BBA certification - we've looked carefully at this and it is also rubbish - having asked for precise details of the tests, and how the claimed results were arrived at, the suppliers ran screaming for the hills.  BBA is a private test organisation, who take money for testing products - and issue so called 'agrement certificates' - which aren't worth the paper they are printed on.  BBA have issued agrement certificates for a variety of 'rising damp' treatments that 'treat' a phenomenon that you can't even reproduce in a laboratory.  

Renotherm traps moisture - it sticks slates and tiles to together, making maintenance impossible - if one of them cracks or spalls, you can't remove and replace it.  Everything is stuck together in a horrible foam impregnated mess.  Water that does get between tiles and slates is then held against the timber battens, rotting them.  It is sprayed over rafters, and traps water into the rafters too.  We have seen entire roofs rotted, and totally unrecoverable.  Normally slates and tiles can be re-used.  When renotherm is used, none of the materials can be used again, and the entire roof is scrap. This puts up the cost of re-roofing dramatically.

Our advice to ANYONE buying a house - DO NOT BUY if there is foam insulation sprayed under the roof.

DO NOT even consider spraying foam insulation under your roof - you will devalue your home by the amount that a new roof will cost, and more.

We dealt with one roof recently, sprayed with renotherm, under diminishing Westmoreland slate.  All of the timber battens were in varying stages of rotting.  Foam had stuck all the slates together, making it impossible to recover them when the roof was stripped. Foam had stuck leadwork to tiles, and timber to lead.  All of the leadwork was scrap - nothing could be recovered, and the roof had to be lifted off in slabs and smashed up.  Total cost of the roof was nearly £200,000 - new diminishing Westmoreland slates had to be sourced from the quarry at huge cost, none being recoverable, and approximately £25,000 worth of lead was skipped because we couldnt strip it out of the foam.  The house was initially on the market for £1.8 million, and price dropped to £900,000 before it sold, the new owner being of the opinion he could save the roof. He then had to sell the property after running out of money to finish the roof when our predictions about the damage caused by the renotherm were shown to be correct.

DO NOT use spray foam on your roof - it will cost you dearly, and you will have a massive inherent fire hazard above your head.

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